THE FLOWER AND THE BEE 



single species have become habituated to a diet of pollen and 

 nectar, and subsequently in some cases structural changes have 

 been developed to insure greater success in the search for food. 



In New England Frost and myself have collected 23'^2 species 

 of beetles, belonging to 127 genera and 29 families which visit 

 flowers. This is probably less than ^V of the total number of 

 described species in this region. In all Europe Knuth has 

 enumerated only 434 anthophilous beetles. Why is it that so 

 few feed on pollen and nectar .^ Their habits and forms, in many 

 instances, answer this question; many are predaceous like the 

 tiger-beetles and ground-beetles, or are scavengers like the 

 rove-beetles; others are nocturnal, or aquatic, or occur chiefly 

 on the ground, lurking beneath stones and boards, or living in 

 the nests of other insects. (Fig. 87.) Many flowers, more- 

 over, have the nectar concealed where it is beyond the reach 

 of beetles, which, with few exceptions, have short tongues. 



Beetles are usually found on common, open flowers with the 

 nectar visible or nearly visible, as the cherries, cornels, shad- 

 bush, New Jersey tea, and goldenrods. In early spring, on the 

 white flowers of the shadbush {Amelanchier canadensis), 31 

 species have been taken, the choke-cherry {Prunus virginiana) 

 (Fig. 88) yielded 43, the chokeberry {Pyrus arbutifolia) 10, and 

 the dense panicles of small white flowers of the meadow-sweet 

 {Spiropa salicifolia) 42, while the flat-topped cymes of the 

 cornels (Cornus) attracted 38 species, and the profusion of 

 flower-clusters, which convert the bushes into huge bouquets, 

 drew to the viburnums (Fig. 89) the phenomenal number of 

 81 kinds. In New England on the New Jersey tea {Ceanothus 

 americanus) 13 species were captured, but in the warmer climate 

 of Virginia, Banks's list of beetles taken on the Ceanothus in- 

 cludes 58 kinds. Among the Compositoe beetles are more com- 

 mon on the flowers of the goldenrod than any other genus; 



180 



